As the technologies relating to space travel have improved, it has become desirable to deploy satellites in either orbital positions around stellar bodies, including Earth, or to direct satellites in trajectories calculated to fly by or to land on stellar bodies in order to collect data about them.
Increasingly, these satellites are being initially deployed, or sometimes repaired, by extravehicular activities (EVA) crew men who, appropriately garbed, exit a manned spacecraft to accomplish these tasks. The deployment of satellites involves several steps in which a satellite is transformed from a compact, tightly packaged unit configured to be shipped into orbit to an unwieldy apparatus which, in some cases, have large solar panels resembling wings, sails, or other configurations. Additionally, antennas and various types of equipment must be electromechanically deployed and supported by struts which in some manner must be compact for shipment into space but capable of being extended during deployment of the satellite.
One such device which is capable of being compactly stored for delivery into space yet extendable to form a support strut once in space is termed a bi-stem. It consists of exterior and interior thin, stainless steel bands, with the exterior band configured to laterally encircle the interior band to form a tubular structure. In order to store these bands for delivery into space, the bands are laterally straightened, and each is rolled onto a roller which is mounted in a cassette. Once in space, the rollers are driven so as to drive the bands out of the cassette, allowing the exterior band to encircle the inner band and form a bi-stem.
Problems have occasionally arisen when attempting to drive the bands out of the cassette, which causes them to become jammed in the cassette. When this occurs, and if the deployment of the satellite is during a manned flight, the astronauts may attempt to free the jammed bi-stem. To do this, they would have to grasp the bi-stem with a gloved hand and attempt to pull it out of the cassette. The problem with this is that a human hand inside a spacesuit glove cannot distribute the force necessary to grasp the bi-stem without crushing or otherwise damaging it. Also, the spacesuit glove is relatively slippery against the smooth bi-stem and would tend to slip. Further, since the bi-stem has an exposed sharp longitudinal seam, the possibility exists that a glove could be punctured by this seam. Thus, in the event that the bi-stem cannot be easily freed, the equipment it supports cannot be properly deployed. In the instance where the jammed bi-stem is used to support or deploy one of several solar panels which generates electrical power for the satellite, then the remaining solar panels may not be able to provide sufficient electrical power for the satellite, which may then become partially or totally disabled. This would be an obviously expensive failure.
It is an object of the present invention to provide a device for application of gripping forces to a cylindrical object, the gripping forces being distributed over a relatively large surface of the cylindrical object.
It is a further object of this invention to provide a device which may be used by extravehicular crew men to free a jammed bi-stem from a cassette in which it is stored.